Article Title
Keywords
h-BN matrix composite ceramics, La–Al–Si–O glass phase, microstructural evolution, nanocrystalline precipitation, mechanical properties
Abstract
BN/La–Al–Si–O composite ceramics were fabricated by hot-pressed sintering using hexagonal boron nitride (h-BN), lanthanum oxide (La2O3), aluminia (Al2O3), and amorphous silica (SiO2) as the raw materials. The effects of sintering temperature on microstructural evolution, bulk density, apparent porosity, and mechanical properties of the h-BN composite ceramics were investigated. The results indicated that La–Al–Si–O liquid phase was formed during sintering process, which provided an environment for the growth of h-BN grains. With increasing sintering temperature, the cristobalite phase precipitation and h-BN grain growth occurred at the same time, which had a significant influence on the densification and mechanical properties of h-BN composite ceramics. The best mechanical properties of BN/La–Al–Si–O composite ceramics were obtained under the sintering temperature of 1700 ℃. The elastic modulus, flexural strength, and fracture toughness were 80.5 GPa, 266.4 MPa, and 3.25 MPa·m1/2, respectively.
Publisher
Tsinghua University Press
Recommended Citation
Baofu QIU, Xiaoming DUAN, Zhuo ZHANG, Chen ZHAO, Bo NIU, Peigang HE, Delong CAI, Lei CHEN, Zhihua YANG, Yujin WANG, Dechang JIA, Yu ZHOU. Microstructural evolution of h-BN matrix composite ceramics with La–Al–Si–O glass phase during hot-pressed sintering. Journal of Advanced Ceramics 2021, 10(3): 493-501.
